inheritance (3)

Question 1

what is the definition of variation?

Answer 1

the difference in traits between individuals of the same species

Question 2

what are the 3 primary sources of genetic variation?

Answer 2

1. sexual reproduction due to meiosis/random fertilisation
2. mutation (deletion, insertion, substitution, frameshift)
3. gene flow/migration: movement of genes from one population to another

Question 3

what are the types of variation?

Answer 3

discontinuous and continuous

Question 4

what is the definition of natural selection?

Answer 4

process in which organisms with desirable genes and characteristics which favour survival are passed on to their offspring through their genes

Question 5

how does mutagens link to evolution?

Answer 5

1. mutations may arise spontaneously due to mutagens
2. variations in organisms arise due to mutations (this variation could be an inheritable change in gene/chromosome structure or chromosome number)
3. this may change the phenotype of an organism which brings about variation within a population (can lead to gene flow)
4. there is different reproductive potential where nature selects varieties which are better suited for survival under prevailing environmental conditions so they will survive and reproduce more
5. with time, selected genes/alleles accumulate as a result of an increase in population of the organisms that are fit to survive. evolution of a new species occurs.

Question 6

what are homologous chromosomes?

Answer 6

1. exist in pair: one chromosome from mother and one chromosome from father
2. have exactly the same order of gene loci: alleles in the gene loci may be different tho
3. similar in shape and size: except Y is shorter than X